The implementations described herein relate generally to aircraft ram air systems, and, more specifically, to an aircraft ram system that is capable of providing cooling to multiple components of the aircraft.
At least some known aircraft include a ram air system that provides ram air to at least one air conditioning (A/C) pack of an aircraft environmental control system (ECS). At least some ram air systems and A/C packs are both positioned within a pack bay of the aircraft, along with other aircraft components. The A/C pack generates heat during operation and discharges the heat into the pack bay and ram exhaust, while supplying cool air to the cabin. The heated air within the pack bay may cause an undesirable increase in temperature of the components within the pack bay and also the surrounding aircraft structure. For example, at least some aircraft include fuel tanks located proximate the pack bay. As such, an increase in pack bay temperature may cause an undesirable increase in fuel temperature. At least some aircraft include an insulation layer between the pack bay and the fuel tanks to reduce fuel heating. However, such insulation increases the overall weight of the aircraft and may require replacement.
The ram air system provides cooling air to the A/C packs, and, more specifically, to a heat exchanger of the A/C pack. As such, the temperature of the exhaust flow of the ram air system is higher compared to the temperature of the inlet flow of ram air into the system and also the free stream airflow. In at least some aircraft, the exhaust from the ram air system flows along downstream skin panels of the aircraft. Continuous exposure to this high temperature ram air exhaust flow may cause unscheduled maintenance of the downstream panels or limit the service lifetime of such panels, especially in the case of carbon fiber panels. At least some known aircraft include a heat shield built into the skin panels downstream of the ram air exhaust. Such heat shields may be simply a thicker, more robust, skin panel, or may include an insulation core to insulate the skin from the hot exhaust flow. In either case, the heat shield may be quite large and relatively heavy as compared to a standard skin panel. Accordingly, such heat shields increase the overall weight of the aircraft and also the manufacturing costs.